Froch beat Groves with a stunning right in the eighth finally ending the
bitter rivalry with a mighty statement

Carl Froch and George Groves were locked into a rivalry that seemed likely to go on forever until the champion ended it with a savage eighth-round knock-out that left Groves with his left leg bent behind him and his mind in another galaxy.

In its execution, this stunning victory for Froch bordered on the unwatchable. Such was the force of the winning punch 2m 34 secs into round eight that Groves will now require careful medical supervision to ensure any side-effects are dealt with.

The right-hand that gave Froch a 2-0 win in the series smashed his young rival off his feet and into a heap. There is obviously no point in staging a third contest, because Froch's lead is unassailable and Groves is clearly ill-equipped to deal with these sudden bursts of power in the later rounds.

He was stopped in the first fight in round nine. This time he was pole-axed in round eight. Box office gold while it lasted, this rivalry was not in the same class as the Nigel Benn-Chris Eubank battles in the same weight class.

A national event, watched by 80,000 at Wembley and an expected million more on pay-per-view, Froch-Groves II began more cautiously than the first bout but soon erupted into violent life, with 'The Cobra' applying measured pressure on his younger opponent and 'St George' Groves seeking victory through jaw-juddering counter-attacking rights.

In the seventh-round, Groves added a sharp left-uppercut to his repertoire and Froch stopped in his tracks to absorb the shock. But the defending champion has a concrete chin and relentless nature. He saps the hope from opponents by refusing to be hurt. He was saving up his final assault.

Groves claimed Froch was “on death row” and facing “his day of reckoning.”

He predicted a victory by left hook. All he probably meant by the death row comment was that Froch was past his best. Some chance. If Froch can somehow avenge his defeat to Andre Ward, the world No 1, he will go down as one of the greatest British fighters. Even without that rematch triumph, he will be remembered as one of the toughest, bravest and most cunning of all British boxers.

Only now he is earning the recognition he deserves.

Watched by Frank Bruno, Eubank, Michael Watson, Naseem Hamed and Amir Khan, this was a celebration of the British fight game: a throwback to the Eubank-Benn animosity of the 1990s. Boxing needs rivalries, above all â€“ especially domestic ones, and this one had the testosterone flowing around Wembley.

However much boxing struggles for attention, week to week, it can always draw on the innate urge on these islands to watch two men fight, with a big pop concert feel, booming tunes, and TV celebs and footballers rubbing expensive threads in the ringside enclosure.

The ring entrances were a rock opera, with flame jets, fireworks and lazers.

“Is this a ringwalk or a posing contest?” the former world heavyweight champion, Lennox Lewis, tweeted. But the crowd was not objecting, even if Groves was left to twitch and stretch for 10 minutes while Froch carried his belts though the throng.

On Friday night here it was paper aeroplanes and good-luck-in-Brazil. Twenty-four hours later, two tribes went to war as Wembley Way heaved with fight fans, most of them committed followers of Froch or Groves.

The first real taste of violence came when Thailand's Tabtimdaeng Na Rachawat was felled by a savage left-hook from the glove of Jamie McDonnell. A One Direction concert, this was not.

In a 12-year career Froch, 36, has lost just twice in 35 bouts, to Andre Ward and Mikkel Kessler (the latter defeat was avenged). Groves, 26, from nearby Hammersmith, had won his first 19 bouts before running into the IBF and WBA super-middleweight champion in Manchester.

In their first fight Froch bounced from a first-round knock-down to win his 11th world title fight with a ninth-round TKO, after a barnstorming sixth. Howard Foster's stoppage of Groves was contentious but followed four blows from Froch to the chin and head. Foster cupped Groves' head in his hands as the fighter crouched on one knee. Froch endorsed that decision: “I had a free shot, and that's when people get hurt in this business,” he said.

That narrative was the perfect frame for the rematch: Groves the first-round whirlwind and superior technician, Froch the indomitable “warrior” and veteran of marquee bouts with Ward, Kessler, Arthur Abraham and Lucian Bute.

Eddie Hearn, the promoter, claimed vindication: “Everyone thought I was crazy, especially my old man [Barry],” he said. “But we're not kamikazes who said 'yeah let's do it at Wembley'. You analyse it, you look at the numbers, you look at the costs.

"My old man is a chartered accountant and he's imbued that in me.”

As it turned out, this was not light entertainment or accountancy. It was a hardened champion with an iron chin crushing a young pretender with a suspect jaw.

Then again no opponent could have absorbed the shot Froch landed on Groves to consign this grudge to history.